Haha! I don't think I have ever found another PhD that I would rather have done than my own, but I have certainly heard what others in the department are up to and thought that I could continue doing PhDs for the rest of my life, because I am so fascinated by what others are doing too. Sometimes I think I don't have enough hours in the day to do everything I would love to do, and wonder how easy it would be to move into a slightly different topic further down the line etc, in addition to continuing to work in my own field. I guess it's good to be inspired by what others are doing, and at the end of the day if you don't find your PhD to be the thing you want to spend the rest of your life doing then you can always shift to a different area once you are equipped with the research skills you need. But yeah, I guess there is always a case of grass is greener etc....KB